Adenosine A2a receptor antagonists

ABSTRACT

Compounds having the structural formula I  
                 
or a pharmaceutically acceptable salt thereof, wherein R is optionally substituted phenyl, cycloalkenyl, or heteroaryl; 
         X is alkylene or —C(O)CH 2 —;    Y is —N(R 2 )CH 2 CH 2 N(R 3 )—, —OCH 2 CH 2 N(R 2 )—, —O—, —S—, —CH 2 S—, —(CH 2 ) 2 —NH—, or optionally substituted  
                 
m and n are 2-3, and Q is nitrogen or optionally substituted carbon; and    Z is optionally substituted phenyl, phenylalkyl or heteroaryl, diphenylmethyl, R 6 —C(O)—, R 6 —SO 2 —, R 6 —OC(O)—, R 7 —N(R 8 )—C(O)—, R 7 —N(R 8 )—C(S)—,  
                 
 
phenyl-CH(OH)—, or phenyl-C(═NOR 2 )—; or when Q is CH, phenylamino or pyridylamino; or 
Z and Y together are substituted piperidinyl or substituted phenyl; and    R 2 , R 3 , R 6 , R 7 , and R 8  are as defined in the specification are disclosed, their use in the treatment of Parkinson&#39;s disease, alone or in combination with other agents for treating Parkinson&#39;s disease, and pharmaceutical compositions comprising them; also disclosed are a processes for preparing intermediates useful for preparing compounds of formula I.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.60/207,143, filed May 26, 2000.

BACKGROUND

The present invention relates to substituted5-amino-pyrazolo-[4,3-e]-1,2,4-triazolo[1,5-c]pyrimidine adenosineA_(2a) receptor antagonists, the use of said compounds in the treatmentof central nervous system diseases, in particular Parkinson's disease,and to pharmaceutical compositions comprising said compounds. Theinvention also relates to a process for preparing5-amino-2-(substituted)pyrazolo[4,3-e]-1,2,4-triazolo-[1,5-c]pyrimidines,intermediates useful in preparing the claimed compounds.

Adenosine is known to be an endogenous modulator of a number ofphysiological functions. At the cardiovascular system level, adenosineis a strong vasodilator and a cardiac depressor. On the central nervoussystem, adenosine induces sedative, anxiolytic and antiepilepticeffects. On the respiratory system, adenosine inducesbronchoconstriction. At the kidney level, it exerts a biphasic action,inducing vasoconstriction at low concentrations and vasodilation at highdoses. Adenosine acts as a lipolysis inhibitor on fat cells and as anantiaggregant on platelets.

Adenosine action is mediated by the interaction with different membranespecific receptors which belong to the family of receptors coupled withG proteins. Biochemical and pharmacological studies, together withadvances in molecular biology, have allowed the identification of atleast four subtypes of adenosine receptors: A₁, A_(2a), A_(2b) and A₃.A₁ and A₃ are high-affinity, inhibiting the activity of the enzymeadenylate cyclase, and A_(2a) and A_(2b) are low-affinity, stimulatingthe activity of the same enzyme. Analogs of adenosine able to interactas antagonists with the A₁, A_(2a), A_(2b) and A₃ receptors have alsobeen identified.

Selective antagonists for the A_(2a) receptor are of pharmacologicalinterest because of their reduced level of side affects. In the centralnervous system, A_(2a) antagonists can have antidepressant propertiesand stimulate cognitive functions. Moreover, data has shown that A_(2a)receptors are present in high density in the basal ganglia, known to beimportant in the control of movement. Hence, A_(2a) antagonists canimprove motor impairment due to neurodegenerative diseases such asParkinson's disease, senile dementia as in Alzheimer's disease, andpsychoses of organic origin.

Some xanthine-related compounds have been found to be A₁ receptorselective antagonists, and xanthine and non-xanthine compounds have beenfound to have high A_(2a) affinity with varying degrees of A_(2a) vs. A₁selectivity. Triazolo-pyrimidine adenosine A_(2a) receptor antagonistswith different substitution at the 7-position have been disclosedpreviously, for example in WO 95/01356; U.S. Pat. No. 5,565,460; WO97/05138; and WO 98/52568.

SUMMARY OF THE INVENTION

The present invention relates to compounds having the structural formulaI

or a pharmaceutically acceptable salt thereof, wherein

-   -   R is R¹-furanyl, R¹-thienyl, R¹-pyridyl, R¹-pyridyl N-oxide,        R¹-oxazolyl, R¹⁰-phenyl, R¹-pyrrolyl or C₄-C₆ cycloalkenyl;    -   X is C₂-C₆ alkylene or —C(O)CH₂—;    -   Y is —N(R²)CH₂CH₂N(R³)—, —OCH₂CH₂N(R²)—, —O—, —S—, —CH₂S—,        —(CH₂)₂—NH—, or        and    -   Z is R⁵-phenyl, R⁵-phenyl(C₁-C₆)alkyl, R⁵-heteroaryl,        diphenylmethyl, R⁶—C(O)—, R⁶—SO₂—, R⁶—OC(O)—, R⁷—N(R⁸)—C(O)—,        R⁷—N(R⁸)—C(S)—,        phenyl-CH(OH)—, or phenyl-C(═NOR²)—; or when Q is        Z is also phenylamino or pyridylamino; or    -   Z and Y together are    -   R¹ is 1 to 3 substituents independently selected from hydrogen,        C₁-C₆-alkyl, —CF₃, halogen, —NO₂, —NR¹²R¹³, C₁-C₆ alkoxy, C₁-C₆        alkylthio, C₁-C₆ alkylsulfinyl, and C₁-C₆ alkylsulfonyl;    -   R² and R³ are independently selected from the group consisting        of hydrogen and C₁-C₆ alkyl;    -   m and n are independently 2-3;    -   Q is    -   R⁴ is 1-2 substituents independently selected from the group        consisting of hydrogen and C₁-C₆alkyl, or two R⁴ substituents on        the same carbon can form ═O;    -   R⁵ is 1 to 5 substituents independently selected from the group        consisting of hydrogen, halogen, C₁-C₆ alkyl, hydroxy, C₁-C₆        alkoxy, —CN, di-((C₁-C₆)alkyl)amino, —CF₃, —OCF₃, acetyl, —NO₂,        hydroxy(C₁-C₆)alkoxy, (C₁-C₆)-alkoxy(C₁-C₆)alkoxy,        di-((C₁-C₆)-alkoxy)(C₁-C₆)alkoxy,        (C₁-C₆)-alkoxy(C₁-C₆)alkoxy-(C₁-C₆)-alkoxy,        carboxy(C₁-C₆)-alkoxy, (C₁-C₆)-alkoxycarbonyl(C₁-C₆)alkoxy,        (C₃-C₆)cycloalkyl(C₁-C₆)alkoxy,        di-((C₁-C₆)alkyl)amino(C₁-C₆)alkoxy, morpholinyl,        (C₁-C₆)alkyl-SO₂—, (C₁-C₆)alkyl-SO—(C₁-C₆)alkoxy,        tetrahydropyranyloxy, (C₁-C₆)alkylcarbonyl(C₁-C₆)-alkoxy,        (C₁-C₆)-alkoxycarbonyl, (C₁-C₆)alkylcarbonyloxy(C₁-C₆)-alkoxy,        —SO₂NH₂, phenoxy,        or adjacent R⁵ substituents together are —O—CH₂—O—,        —O—CH₂CH₂—O—, —O—CF₂—O— or —O—CF₂CF₂—O— and form a ring with the        carbon atoms to which they are attached;    -   R⁶ is (C₁-C₆)alkyl, R⁵-phenyl, R⁵-phenyl(C₁-C₆)alkyl, thienyl,        pyridyl, (C₃-C₆)-cycloalkyl,        (C₁-C₆)alkyl-OC(O)—NH—(C₁-C₆)alkyl—,        di-((C₁-C₆)alkyl)aminomethyl, or    -   R⁷ is (C₁-C₆)alkyl, R⁵-phenyl or R⁵-phenyl(C₁-C₆)alkyl;    -   R⁸ is hydrogen or C₁-C₆ alkyl; or R⁷ and R⁸ together are        —(CH₂)_(p)—A—(CH₂)_(q), wherein p and q are independently 2 or 3        and A is a bond, —CH₂—, —S— or —O—, and form a ring with the        nitrogen to which they are attached;    -   R⁹ is 1-2 groups independently selected from hydrogen, C₁-C₆        alkyl, hydroxy, C₁-C₆ alkoxy, halogen, —CF₃ and        (C₁-C₆)alkoxy(C₁-C₆)alkoxy;    -   R¹⁰ is 1 to 5 substituents independently selected from the group        consisting of hydrogen, halogen, C₁-C₆ alkyl, hydroxy, C₁-C₆        alkoxy, —CN, —NH₂, C₁-C₆alkylamino, di-((C₁-C₆)alkyl)amino,        —CF₃, —OCF₃ and —S(O)₀₋₂(C₁-C₆)alkyl;    -   R¹¹ is H, C₁-C₆ alkyl, phenyl, benzyl, C₂-C₆ alkenyl, C₁-C₆        alkoxy(C₁-C₆)alkyl, di-((C₁-C₆)alkyl)amino(C₁-C₆)alkyl,        pyrrolidinyl(C₁-C₆)alkyl or piperidino(C₁-C₆)alkyl;    -   R¹² is H or C₁-C₆ alkyl; and    -   R¹³ is (C₁-C₆)alkyl-C(O)— or (C₁-C₆)alkyl-SO₂—.

Preferred compounds of formula I are those wherein R is R¹-furanyl,R¹-thienyl, R¹-pyrrolyl or R¹⁰-phenyl, more preferably R¹-furanyl. R¹ ispreferably hydrogen or halogen. Another group of preferred compounds isthat wherein X is alkylene, preferably ethylene. Y is preferably

wherein Q is

with Q preferably being nitrogen. Preferably, m and n are each 2, and R⁴is H. A preferred definition for Z is R⁵-phenyl, R⁵-heteroaryl, R⁶—C(O)—or R⁶—SO₂—. R⁵ is preferably H, halogen, alkyl, alkoxy, hydroxyalkoxy oralkoxyalkoxy. R⁶ is preferably R⁵-phenyl.

Another aspect of the invention is a pharmaceutical compositioncomprising a therapeutically effective amount of a compound of formula Iin a pharmaceutically acceptable carrier.

Yet another aspect of the invention is a method of treating centralnervous system diseases such as depression, cognitive diseases andneurodegenerative diseases such as Parkinson's disease, senile dementiaor psychoses of organic origin, and stroke, comprising administering acompound of formula I to a mammal in need of such treatment. Inparticular, the invention is drawn to the method of treating Parkinson'sdisease comprising administering a compound of formula I to a mammal inneed of such treatment.

Another aspect of the invention is a process for preparing5-amino-2-(R-substituted)-pyrazolo[4,3-e]-1,2,4-triazolo-[1,5-c]pyrimidinesof formula II, which are intermediates useful in the preparation ofcompounds of formula I. The process of preparing compounds of formula II

wherein R is as defined above, comprises

-   -   (1) treating 2-amino-4,6-dihydroxypyrimidine        with POCl₃ in dimethylformamide (DMF) to obtain        2-amino4,6-dichloropyrimidine-5-carboxaldehyde    -   (2) treating carboxaldehyde VII with a hydrazide of the formula        H₂N—NH—C(O)—R, wherein R is as defined above, to obtain    -   (3) treating the intermediate of formula VIII with hydrazine        hydrate to form a pyrazolo ring, thus obtaining the intermediate        of formula IX    -   (4) forming the desired compound of formula II by dehydrative        rearrangement.

A preferred aspect of the process is the dehydrative rearrangement ofthe intermediate of formula IX to obtain the5-amino-2-(R-substituted)-pyrazolo[4,3-e]-1,2,4-triazolo[1,5-c]pyrimidineof formula II. Preferred embodiments of the process use 2-furoichydrazide or 2-thienoylhydrazide in step 2, thus preparing compounds offormula II wherein R is 2-furyl or 2-thienyl.

Another aspect of the invention is a process for preparing7-bromoalkyl-5-amino-2-(R-substituted)-pyrazolo[4,3-e]-1,2,4-triazolo-[1,5-c]pyrimidines of formula IIIa,which are intermediates useful in the preparation of compounds offormula I. The process of preparing compounds of formula IIIa

wherein R is as defined above, comprises

-   -   (1) treating a chloride of formula VIII        with a hydroxyalkyl hydrazine of the formula HO—(CH₂)_(r)—NHNH₂,        wherein r is 2-6, to obtain    -   (2) cyclizing the intermediate of formula X by dehydrative        rearrangement to obtain the tricyclic intermediate of formula XI    -   (3) converting the hydroxy compound of formula XI to the bromide        of formula IIIa.

Still another aspect of the invention is a method of treatingParkinson's disease with a combination of a compound of formula I andone or more agents known to be useful in the treatment of Parkinson'sdisease, for example dopamine; a dopaminergic agonist; an inhibitor ofmonoamine oxidase, type B (MAO-B); a DOPA decarboxylase inhibitor (DCI);or a catechol-O-methyltransferase (COMT) inhibitor. Also claimed is apharmaceutical composition comprising a compound of formula I and one ormore agents known to be useful in the treatment of Parkinson's in apharmaceutically acceptable carrier.

DETAILED DESCRIPTION

As used herein, the term alkyl includes straight or branched chains.Alkylene, referring to a divalent alkyl group, similarly refers tostraight or branched chains. Cycloalkylene refers to a divalentcycloalkyl group. Cycloalkenyl refers to a C₄-C₆ cycloalkyl ringcomprising one double bond.

Heteroaryl means a single ring, bicyclic or benzofused heteroaromaticgroup of 5 to 10 atoms comprised of 2 to 9 carbon atoms and 1 to 4heteroatoms independently selected from the group consisting of N, O andS, provided that the rings do not include adjacent oxygen and/or sulfuratoms. N-oxides of the ring nitrogens are also included. Examples ofsingle-ring heteroaryl groups are pyridyl, oxazolyl, isoxazolyl,oxadiazolyl, furanyl, pyrrolyl, thienyl, imidazolyl, pyrazolyl,tetrazolyl, thiazolyl, isothiazolyl, thiadiazolyl, pyrazinyl, pyrimidyl,pyridazinyl and triazolyl. Examples of bicyclic heteroaryl groups arenaphthyridyl (e.g., 1, 5 or 1,7), imidazopyridyl, pyrido[2,3]imidazolyl,pyridopyrimidinyl and 7-azaindolyl. Examples of benzofused heteroarylgroups are indolyl, quinolyl, isoquinolyl, phthalazinyl, benzothienyl(i.e., thionaphthenyl), benzimidazolyl, benzofuranyl, benzoxazolyl andbenzofurazanyl. All positional isomers are contemplated, e.g.,2-pyridyl, 3-pyridyl and 4-pyridyl. R⁵-substituted heteroaryl refers tosuch groups wherein substitutable ring carbon atoms have a substituentas defined above.

Certain compounds of the invention may exist in different stereoisomericforms (e.g., enantiomers, diastereoisomers and atropisomers). Theinvention contemplates all such stereoisomers both in pure form and inmixture, including racemic mixtures.

Certain compounds will be acidic in nature, e.g. those compounds whichpossess a carboxyl or phenolic hydroxyl group. These compounds may formpharmaceutically acceptable salts. Examples of such salts may includesodium, potassium, calcium, aluminum, gold and silver salts. Alsocontemplated are salts formed with pharmaceutically acceptable aminessuch as ammonia, alkyl amines, hydroxyalkylamines, N-methylglucamine andthe like.

Certain basic compounds also form pharmaceutically acceptable salts,e.g., acid addition salts. For example, pyrido-nitrogen atoms may formsalts with strong acid, while compounds having basic substituents suchas amino groups also form salts with weaker acids. Examples of suitableacids for salt formation are hydrochloric, sulfuric, phosphoric, acetic,citric, oxalic, malonic, salicylic, malic, fumaric, succinic, ascorbic,maleic, methanesulfonic and other mineral and carboxylic acids wellknown to those skilled in the art. The salts are prepared by contactingthe free base form with a sufficient amount of the desired acid toproduce a salt in the conventional manner. The free base forms may beregenerated by treating the salt with a suitable dilute aqueous basesolution such as dilute aqueous NaOH, potassium carbonate, ammonia andsodium bicarbonate. The free base forms differ from their respectivesalt forms somewhat in certain physical properties, such as solubilityin polar solvents, but the acid and base salts are otherwise equivalentto their respective free base forms for purposes of the invention.

All such acid and base salts are intended to be pharmaceuticallyacceptable salts within the scope of the invention and all acid and basesalts are considered equivalent to the free forms of the correspondingcompounds for purposes of the invention.

Compounds of formula I can be prepared by known methods from startingmaterials either known in the art or prepared by methods known in theart; see, for example, WO 95/01356 and J. Med. Chem., 39 (1996)1164-1171.

Preferably, the compounds of formula I are prepared by the methods shownin the following reaction schemes. In Scheme 1, alkylation of a5-amino-pyrazolo[4,3-e]-[1,2,4]-triazolo[1,5-c]pyrimidine of formula IIis used to prepare compounds of formula I:

Starting materials of formula II can be reacted with an alkyl diolditosylate and a base such as NaH in an inert solvent such asdimethylformamide (DMF), or with a chloro-bromo- or dibromo-alkylcompound under similar conditions, to obtain the alkyl-substitutedintermediate of formula III. The compound of formula III is then reactedwith an amine of the formula Z—Y—H in an inert solvent such as DMF at anelevated temperature to obtain a compound of formula Ia, i.e., acompound of formula I wherein X is alkylene.

Alternatively, staring materials of formula II can be reacted with acompound of formula Z—Y—X—Cl and a base such as NaH in an inert solventsuch as DMF to obtain a mixture of a 7-substituted compound of formula Iand the corresponding 8-substituted compound.

To prepare compounds of formula I wherein Y is piperazinyl and Z isR⁶—C(O)—, R⁶—SO₂—, R⁶—OC(O)—, R⁷—N(R⁸)—C(O)— or R⁷—N(R⁸)—C(S)—, acompound of formula I wherein Z—Y is 4-t-butoxycarbonyl-1-piperazinyl isdeprotected, for example by reaction with an acid such as HCl. Theresultant free piperazinyl compound, IV, is treated according toprocedures well known in the art to obtain the desired compounds. Thefollowing Scheme 2 summarizes such procedures:

Another method for preparing compounds of formula I is shown in Scheme3:

In this procedure, chloropyrazolo-pyrimidine V is reacted with acompound of formula Z—Y—X—Cl in a manner similar to the alkylationprocedure of Scheme 1, and the resultant intermediate is reacted with ahydrazide of formula H₂N—NH—C(O)—R (or with hydrazine hydrate, followedby a compound of formula Cl—C(O)—R). The resultant hydrazide undergoesdehydrative rearrangement, e.g., by treatment withN,O-bis-(trimethylsilyl)acetamide (BSA) or a combination of BSA andhexamethyidisilazane (HMDS) and at elevated temperatures.

Starting materials are known or can be prepared by processes known inthe art. However, compounds of formula II are preferably prepared by thenovel process disclosed above and described in further detail here.

In the first step of the process, 2-amino-4,6-dihydroxypyrimidine (VI)is converted to the corresponding 4,6-dichloro-5-carboxaldehyde bytreatment with POCl₃ or SOCl₂ in DMF as described in Helv. Chim. Acta,69 (1986), 1602-1613. The reaction is carried out at an elevatedtemperature, preferably about 100° C., for 2 to 8 hours, preferablyabout 5 hours.

In the second step, 2-amino-4,6-dichloropyrimidine-5-carboxaldehyde(VII) is treated with a hydrazide of the formula H₂N—NH—C(O)—R, whereinR is as defined above, to obtain the compound of formula VIII; thecompound of formula VI and the hydrazide are used in a molar ratio ofapproximately 1:1, with a slight excess of the hydrazide beingpreferred. The reaction is carried out at room temperature or up toabout 80° C. in a solvent such as CH₃CN or DMF. The reaction time isabout 16 hours (e.g., overnight).

In the third step, the compound of formula VIII is heated at 60-100° C.with 1-5 equivalents of hydrazine hydrate in a solvent such as CH₃CN orDMF for 1-24 hours to obtain the compound of formula IX.

In the last step, the compound of formula IX undergoes dehydrativerearrangement by treatment with a mixture of HMDS and BSA or with BSAalone. The reaction is carried out at elevated temperatures, preferablyabout 120° C., for about 16 hours (e.g., overnight)

After each step of the process, the crude material is purified byconventional methods, e.g., extraction and/or recrystallization.

Compared to previously published methods for preparing the intermediateof formula II, this method proceeds in fewer steps, under milderreaction conditions and with much higher yield.

The compounds of formulas V and VII are known (Helv. Chim. Acta, 69(1986), 1602-1613).

Another method for preparing compounds of formula I is illustrated inthe following Scheme 4.

Chloride VIII is treated with a hydroxyalkyl-hydrazine in an inertsolvent such as ethanol at temperatures from ambient to 100° C. tofurnish derivative X. This is subjected to dehydrative cyclization,similarly to IX, such as with BSA, to provide tricyclic XI. Tricyclic XIis then converted to bromide IIIa with PBr₃ at elevated temperature from80° C. to 150° C. for 1 to 24 hours. Intermediate XI can also beconverted into the tosylate analogous to IIIa by toluenesulfonylchloride and base. Bromide IIIa is converted to compounds of formula Ias described above for III.

Another method for preparing compounds of formula I is illustrated inthe following Scheme 5:

In analogy to Scheme 1, chloride V is converted into alkylated compoundXII, and this is further reacted with carbazate XIV, where R′ ispreferably t-butyl or benzyl, to obtain derivative XIII. A solvent suchas DMF may be employed at a temperature of 60-120° C. This is thenreacted as in Scheme 1 to furnish XV. The R′ group is next removed, suchas removal of a t-butyl group with HCl or TFA, furnishing hydrazine XVI.Acylation of XVI furnishes XVII, which is subjected to dehydrativecyclization as described above to provide desired Ia. Alternatively, XIImay be reacted with a hydrazide XVIII to obtain XIX, which can beconverted to XVII analogously to preparation of XV.

Using the above procedures, the following compounds were prepared.

Step 1: Stir POCl₃ (84 ml, 0.9 mol) and chill to 5-10° C. while addingDMF (17.8 ml, 0.23 mol ) drop-wise. Allow the mixture to warm to roomtemperature (RT) and add 2-amino-4,6-dihydroxypyrimidine VI (14 g, 0.11mol) portion-wise. Heat at 100° C. for 5 h. Strip off excess POCl₃ undervacuum, pour the residue into ice water, and stir overnight. Collectsolids by filtration and recrystallize the dried material from afiltered ethyl acetate (EtOAc) solution to give the aldehyde, VII, m.p.230° (dec). Mass spectrum: M+=192. PMR (DMSO): δ 8.6(δ, 2H); δ10.1(s,1H).Step 2: Stir a mixture of the product of Step 1 (0.38 g, 2 mmol) and2-furoic hydrazide (0.31 g, 2.5 mmol) in CH₃CN (50 ml ) containingN,N-diisopropylethylamine (0.44 ml, 2.5 mmol) overnight at RT. Solventstrip the reaction mixture, and partition the residue between EtOAc andwater. Dry the organic layer over MgSO₄, remove the solvent, andrecrystallize the residue from CH₃CN to give the desired compound VIII.Mass spectrum: MH+=282.Step 3: Add hydrazine hydrate (75 mg, 1.5 mmol) to a hot CH₃CN solutionof the product of Step 2 (0.14 g, 0.5 mmol). Reflux 1 h. Cool to RT andcollect the yellow product IX. Mass spectrum: MH+=260.Step 4: Heat the product of Step 3 (5.4 g, 0.021 mol) in a mixture ofhexamethyl-disilazine (100 ml) and N,O-bis(trimethylsilyl) acetamide (35ml) at 120° C. overnight. Remove volatiles under vacuum and slurry theresidue in hot water to give a solid precipitate. Recrystallize from 80%aqueous acetic acid to give the title compound. M.P.>300° C. Massspectrum: MH+=242.

Combine the product of Preparation 1 (6.0 g, 25 mmol), ethylene glycolditosylate (11.1 g, 30 mmol), and NaH (60% in oil, 1.19 g, 30 mmol) indry DMF (30 ml). Stir under N₂ for 24 h and filter to obtain the titlecompound as a cream solid (PMR in DMSO: δ4.47+4.51 triplets, 8.03 s).Isolate additional material by chromatography of the filtrate.

In a similar manner to Preparation 1, but employing 2-thienoylhydrazide,prepare the title compound as a yellow solid, mass spectrum: MH+=258.

In a similar manner to Preparation 2, but using the product ofPreparation 3, prepare the title compound as a yellow solid, PMR (DMSO)δ 4.49+4.54 triplets, 8.05 s.

Preparation 5

Arylpiperazines

1-(2,4-Difluorophenyl)piperazine is prepared from2,4-difluorobromobenzene. To the bromide (8.0 g, 41.4 mmol), piperazine(21.4 g, 249 mmol), sodium t-butoxide (5.6 g, 58 mmol) and BINAP (1.55g, 2.5 mmol) in toluene (20 ml), add Pd₂(dba)₃ (0.477 g, 0.83 mmol).Heat the mixture at 110° C. under N₂ for 20 h. Allow to cool and extractwith 1N HCl. Basify the extract with NaOH to pH=10, extract with CH₂Cl₂,dry and concentrate to obtain the title compound as a brown oil.

In a similar fashion, prepare the following arylpiperazines (Me ismethyl):

1-(5-Ethyl-2-pyrimidinyl)piperazine is prepared from2-chloro-5-ethylpyrimidine. Heat the chloride (2.0 g, 14 mmol) andpiperazine (3.0 g, 35 mmol) in EtOH (70 ml) at 90° C. for 2 h in asealed vessel. Concentrate and partition between CH₂Cl₂ and 2N NaOH. Drythe organic with MgSO₄ and concentrate. Chromatograph the crude producton silica (CH₂Cl₂—CH₃OH) to obtain the piperazine as a yellow oil.

In a similar fashion, prepare the following piperazines from theappropriate chloride:

1-(4-Cyano-2-fluorophenyl)piperazine is prepared from3,4-difluorobenzonitrile. Heat the nitrile (2.0 g, 14.4 mmol),piperazine (6.2 g, 72 mmol) and K₂CO₃ (2.4 g, 17 mmol) in toluene (10ml) at reflux for 22 h. Allow to cool, and extract with 1N HCl. Basifywith NaOH to pH=10. Extract with CH₂Cl₂ and wash with water and thenbrine. Dry the organic with MgSO₄ and concentrate to give the piperazineas a white solid.

In a similar fashion, prepare the following piperazines from theappropriate fluoride (Et is ethyl):

1-(4-(2-Methoxyethoxy)phenyl)piperazine is prepared from4-(4-hydroxy-phenyl)-1-acetylpiperazine. To NaH (60% in mineral oil,0.79 g, 20 mmol) in DMF (25 ml) add the phenol (3.0 g, 13.6 mmol),followed by 2-bromoethyl methyl ether (2.27 g, 16.3 mmol). Stir at RT 18h, concentrate, and partition between EtOAc and 5% citric acid. Wash theorganic with 1N NaOH, then brine. Dry over MgSO₄, and concentrate toobtain the alkylated product as a white solid. Heat this material (2.2g, 7.9 mmol) in 6N HCl (30 ml) at reflux for 1 h. Allow to cool andbasify to pH=10 with NaOH. Extract with CH₂Cl₂ and wash with water andthen brine. Dry the organic with MgSO₄ and concentrate to give thepiperazine as a yellow oil.

In a similar fashion (except basic hydrolysis is employed for thecyclopropyl-methyl ether) prepare the following piperazines:

4-(2-Methylaminoethoxy)fluorobenzene is prepared from4-(2-bromo-ethoxy)-fluorobenzene. Combine the bromide (1.0 g, 4.6 mmol)in CH₃OH (5 ml) with CH₃NH₂ in CH₃OH (2M, 46 ml, 92 mmol) in a sealedvessel. Heat at 60° C. for 18 h, concentrate, and partition betweenEtOAc and sat. NaHCO₃. Wash the organic with brine, dry with MgSO₄, andconcentrate to obtain the amine as a yellow oil.

N-methyl-2-(4-(2-methoxyethoxy)phenoxy)ethylamine was prepared in twosteps. Combine 4-(2-methoxyethoxy)phenol (1.68 g, 10.0 mmol),1,2-dibromoethane (16.9 g, 90 mmol), and K₂CO₃ (2.76 g, 20 mmol) inCH₃CN (20 ml) and DMF (10 ml). Heat at reflux 22 h, allow to cool,filter, and partition between ether (Et₂O) and 1N NaOH. Wash with brine,dry over MgSO₄, and concentrate to provide the bromoethyl ether as beigesolid. Combine this (0.97 g, 3.5 mmol) with 2M CH₃NH₂/CH₃OH (35 ml).Heat in a sealed tube (65° C., 18 h), concentrate, and partition betweenEt₂O and 1N NaHCO₃. Wash with brine, dry MgSO₄, and concentrate toprovide the amine as an orange oil.

1-Phenyl-2-piperazinone is prepared from4-benzyloxycarbonyl-1-phenyl-2-piperazinone. Combine this material (1.61g, 5.2 mmol) with 10% Pd/C (0.4 g) in EtOH (50 ml) and 1N HCl (6 ml).Hydrogenate at 45 psi for 2 h and filter. Concentrate and chromatographthe residue on silica (eluting with CH₂Cl₂:CH₃OH:NH₄OH) to obtain thepiperazinone as a cream solid.

Step 1: Dissolve the product of Preparation 1, Step 2 (0.56 g, 2.0 mmol)in hot CH₃CN (200 ml). Add 2-hydroxyethylhydrazine (0.51 g, 6.0 mmol).Heat at reflux 2 h and concentrate. Treat with 25 ml water and stir togive a solid. Collect and dry to give the alcohol, MS: m/e=304 (M+1).Step 2: Heat the product of Step 1 (0.10 g, 0.33 mmol) in BSA (10 ml)for 4 h at 115° C. Concentrate in vacuo and warm with aqueous CH₃OH.Collect and dry to give the cyclization product, MS: m/e=286 (M+1).Step 3: Combine the product of Step 2 (0.285 g, 1.0 mmol) and PBr₃ (2.0ml, 21 mmol). Heat at 145° C. for 2 h, cool, and pour onto ice. Filterand dry the solid. Recrystallize from CH₃OH to obtain the titlecompound, MS: m/e=348+350 (M+1).

Combine 5-bromo-2-furoic acid (0.50 g, 2.6 mmol) and NaHCO₃ (0.44 g, 5.2mmol) in hexane (6 ml) and water (5.2 ml). Add Selectfluor® (0.98 g, 2.8mmol) and stir 2 h. Separate the hexane layer and dry over MgSO₄ toprovide a solution of 2-bromo-5-fluorofuran. Dilute with THF (6 ml) andcool to −78° C. Add 2.5M n-BuLi/hexane (4.2 ml, 11 mmol). Stir 10 min.,add excess dry ice, and stir 1 h additional. Treat with 1N HCl, extractwith CH₂Cl₂, and dry over MgSO₄. Concentrate and dry to obtain the titlecompound as a white solid, PMR (CDCl₃) δ6.70+7.28.

EXAMPLE 1

Combine the tosylate of Preparation 2 (0.55 g, 1.25 mmol) and1-(2,4-difluorophenyl)piperazine (0.50 g, 2.5 mmol) in DMF (7 ml) andheat at 80° C. for 20 h. Concentrate and purify by flash columnchromatography (CH₂Cl₂, CH₃OH+NH₃) to obtain the title compound as acream solid, mass spectrum m/e=466 (M+H).

In similar fashion, prepare the following compounds:

Example Z—Y— MS, [M + 1] m/e 1-2

430 1-3

498 ,500, 502 1-4

498 1-5

444 1-6

431 1-7

460 1-8

448 1-9

404 1-10

520 1-11

498 1-12

532, 534 1-13

478, 480 1-14

494, 496 1-15

444 1-16

478, 480 1-17

464, 466 1-18

432 1-19

468 1-20

431 1-21

472 1-22

508, 510 1-23

490 1-24

490 1-25

445 1-26

460 1-27

455 1-28

533, 535 1-29

437 1-30

481 1-31

498, 500, 502 1-32

448 1-33

432 1-34

444 1-35

474 1-36

498, 500, 502 1-37

470 1-38

466 1-39

462 1-40

460 1-41

484 1-42

499 1-43

480 1-44

462 1-45

474 1-46

478 1-47

484 1-48

517 1-49

473 1-50

478 1-51

484 1-52

474 1-53

492 1-54

514 1-55

450 1-56

493 1-57

473 1-58

500 1-59

462 1-60

447 1-61

445 1-62

504 1-63

488 1-64

502 1-65

510 1-66

482, 484 1-67

478 1-68

534 1-69

480 1-70

496 1-71

496 1-72

444 1-73

491 1-74

578 1-75

520 1-76

522 1-77

560 1-78

500 1-79

508 1-80

532 1-81

540 1-82

468 1-83

490 1-84

572 1-85

540 1-86

522 1-87

518 1-88

529 1-89

574 1-90

572 1-91

528 1-92

572 1-93

529 1-94

522 1-95

548 1-96

548 1-97

437 1-98

518 1-99

532 1-100

504 1-101

518 1-102

479, 501 1-103

401 1-104

454 1-105

507, 509 1-106

443 1-107

471 1-108

457 1-109

401 1-110

440 1-111

485 1-112

429 1-113

499 1-114

461 1-115

446 1-116

475 1-117

473 1-118

474 1-119

458 1-120

446 1-121

446 1-122

490 1-123

528, 530, 532 1-124

460 1-125

458 1-126

458 1-127

445 1-128

523, 525 1-129

515 1-130

518 1-131

493 1-132

548 1-133

493 1-134

530 1-135

507 1-136

487 1-137

531 1-138

487 1-139

531 1-140

494 1-141

419 1-142

461, 463 1-143

459 1-144

441 1-145

457 1-146

431 1-147

407

EXAMPLE 2

Combine the product of Preparation 1 (0.60 g, 2.5 mmol),1,3-dibromopropane (0.60 g, 3.0 mmol), and NaH (60% in oil, 0.119 g, 3.0mmol) in dry DMF (9 ml). Stir under N₂ for 2 h, concentrate and flashchromatograph to obtain the title compound as a solid (PMR inCDCl₃+CD₃OD: δ 2.43 quint., 3.38+4.51 triplets, 8.09 s), as well as8-substituted isomer.

Step 2:

Combine the product of Step 1 (0.050 g, 0.14 mmol) and1-phenylpiperazine (0.045 g, 0.28 mmol) in DMF (2 ml) and heat at 80° C.for 4 h. Concentrate and purify by flash column chromatography (CH₂Cl₂,CH₃OH+NH₃) to obtain the title compound as a cream solid, mass spectrumm/e=443 (M+H).

Similarly prepare the following compounds:

Example Z MS, [M + 1] m/e 2-2

478, 480 2-3

474

EXAMPLE 3

The compound of Example 1-2 was also prepared by the followingprocedure:

Combine the product of Preparation 1 (0.15 g, 0.62 mmol),1-phenyl-4-(2-chloroethyl)piperazine (0.17 g, 0.75 mmol), and NaH (60%in oil, 0.035 g, 0.87 mmol) in dry DMF (7 ml). Stir under N₂ for 48 h,add additional chloride (0.03 g) and NaH (0.005 g) and stir another 72h. Concentrate and purify by flash column chromatography (CH₂Cl₂,CH₃OH+NH₃) to obtain the title compound as a cream solid, mass spectrumm/e=429 (M+H).

The compound of Example 1-3 is similarly prepared, as are the followingcompounds:

Example Z—Y—X— MS, m/e 3-1

454 3-2

444 3-3

429

EXAMPLE 4

Combine 1-(2,4-difluorophenyl)piperazine (1.5 g, 7.6 mmol), ethyl2-bromopropionate (1.65 g, 9.1 mmol) and DIPEA (1.1 g, 8.3 mmol) in DMF(8 ml). Stir 4 h, concentrate, and partition between Et₂O and water.Wash with brine, dry (MgSO₄), and concentrate to obtain the ester as ayellow oil, NMR (CDCl₃) consistent.

To the product of Step 1 (2.15 g, 7.2 mmol) in THF (10 ml), add LiAlH₄(1.0 M in THF, 4.4 ml, 4.4 mmol) dropwise. Heat at 60° C. 1 h, add water(0.16 ml), 15% NaOH (0.16 ml), and then water (0.49 ml). Filter andconcentrate to obtain the alcohol as a yellow oil, NMR (CDCl₃)consistent.

To the product of Step 2 (0.90 g, 3.5 mmol) in CH₂Cl₂ (10 ml) at 5° C.,add SOCl₂ (0.38 ml, 5.3 mmol). Allow to warm and stir 16 h. Concentrateand partition between CH₂Cl₂ and 1N NaOH, wash with water, dry (MgSO₄)and concentrate to obtain the crude product as a yellow oil.

Step 4: Combine the product of Preparation 1 (0.20 g, 0.83 mmol), theproduct of Step 3 (0.34 g, 1.2 mmol) and NaH (60% in oil, 0.040 g, 1.0mmol) in dry DMF (5 ml). Heat at 60° C. for 24 h, add additionalchloride (0.15 g) and NaH (0.02 g), and heat another 4 h. Concentrateand purify by flash column chromatography (CH₂Cl₂, CH₃OH+NH₃) to obtainthe title compound as a yellow solid, mass spectrum m/e=479 (M+H).

Similarly, prepare the following:

EXAMPLE 5

Using the procedure of Example 1, substituting the tosylate ofPreparation 4 for the tosylate of Preparation 2, prepare the followingcompounds:

Ex. Z MS, [M + 1] m/e 5-1

482 5-2

520 5-3

538

EXAMPLE 6

Step 1: To a solution of the product of Example 3-1 (4.17 g, 9.2 mmol)in CH₂Cl₂ (500 ml), add anhydrous HCl (120 ml of 4.0 M dioxane solution)and stir 2 h. Concentrate to dryness under vacuum and take up theresidue in water. Make alkaline with aqueous NaOH and collect theprecipitated de-protected product. Mass spectrum: MH+=354.Step 2: Stir a mixture of the product of Step 1 (71 mg, 0.2 mmol) and4-methoxy-benzoyl chloride (51 mg, 0.3 mmol) in dry DMF (10 ml)containing N,N-diisopropyl-ethylamine (52 mg, 0.4 mmol) for 6 h at RT.Pour the solution into water and collect the precipitated titlecompound. Mass spectrum: MH+=488.

In a similar fashion, prepare the following:

Example Z— MS, [M + 1] m/e 6-2

502 6-3

396 6-4

594 6-5

464 6-6

438 6-7

464 6-8

459 6-9

472 6-10

452 6-11

539 6-12

532 6-13

508 6-14

551 6-15

439 6-16

492

EXAMPLE 7

To a solution of the product of Example 6, Step 1 (53 mg, 0.15 mmol) inNMP (10 ml) add 4-chlorophenylisocyanate (25.3 mg, 0.165 mmol) at RT.Stir overnight, add an additional 25.3 mg of the isocyanate, and stir 1h to complete conversion of all starting material. Pour into water andcollect the precipitated title compound. Mass spectrum: MH+=507.

In a similar fashion, prepare the following from the appropriateisocyanate, isothiocyanate or carbamoyl chloride:

Example Z— MS, [M + 1] m/e 7-2

517 7-3

451 7-4

453 7-5

491 7-6

509 7-7

467

EXAMPLE 8

Slurry the product of Example 6, Step 1 (53 mg, 0.15 mmol) in dry DMF(20 ml) containing triethylamine (77 mg, 0.76 mmol); add2,4-difluorobenzenesulfonyl chloride (37 μl, 0.225 mmol). Stir at RT 2days. Pour into water and collect the precipitated title compound. Massspectrum: M+=529.

In a similar fashion, prepare the following:

Example Z— MS, [M + 1] m/e 8-2

561, 563, 565 8-3

529 8-4

571, 573 8-5

511 8-6

554 8-7

524 8-8

446

EXAMPLE 9

Add 4-methoxyphenyl chloroformate (56 mg, 0.3 mmol) to a slurry of theproduct of Example 6, Step 1 (71 mg, 0.2 mmol) in warm DMF (25 ml)containing triethylamine (101 mg, 1.0 mmol). Stir the mixture overnightat RT. Concentrate the solution to ⅓ its volume and pour into water.Collect the precipitate, wash with water, and dry in vacuo.Recrystallize from CH₃OH/CH₂Cl₂ to give the title compound. Massspectrum: MH+=504.

EXAMPLE 10

Step 1: Combine 1-bromo-2,4-difluorobenzene (1.00 g, 5.18 mmol),N,N′-dimethyl-ethylenediamine (2.74 g, 31.1 mmol), NaO—t—Bu (0.70 g, 7.2mmol), Pd(dba)₂ (0.060 g, 0.10 mmol) and (±)-BINAP (0.19 g, 0.31 mmol)in toluene (10 ml). Heat at 110° for 18 h, allow to cool, and extractwith 1N HCl. Basify the aqueous solution with NaOH and extract withCH₂Cl₂. Dry, concentrate, and purify by PLC to giveN-(2,4-difluoro-phenyl)-N,N′-dimethylethylenediamine.Step 2: Combine the product of Preparation 2 (0.100 g, 0.23 mmol) withthe product of Step 1 (0.091 g, 0.46 mmol) in DMF (2 ml). Heat at 80°for 90 h, allow to cool, concentrate, and purify by columnchromatography to obtain the title compound as an oil, mass specm/e=467.

EXAMPLE 11

The compound of Example 1-2 was also prepared by the followingprocedure.

To a solution of the product of Preparation 1, Step 1, (768 mg, 4 mmol)in DMF (20 ml) add N,N-diisopropylethylamine (0.88 ml, 5 mmol), followedby hydrazine hydrate (0.2 ml, 4.1 mmol). The solution warms and a solidprecipitates which gradually dissolves over 1 h. After stirring 3 h,concentrate the solution under vacuum to about ⅓ its volume, and pourinto water. Collect the precipitate and recrystallize it from CH₃OH togive the chloropyrazolopyrimidine. Mass spectrum: MH+=170.Step 2:

To a stirred solution of 1-phenylpiperazine (6.5 g, 40 mmol) and 50%aqueous chloroacetaldehyde (6.4 ml, 48 mmol) in CH₂Cl₂ (125 ml) at 5-10°C. add, portionwise, Na(OAc)₃BH (12.72 g, 60 mmol). When foaming ceases,allow the mixture to warm to RT and stir for 3 h. Dilute with CH₂Cl₂(100 ml), and shake with 1N aq NaOH to bring pH above 8. Wash organiclayer with water and brine, dry over MgSO₄, and solvent strip.Chromatograph on silica and elute with 1% CH₃OH/CH₂Cl₂ to give the titlecompound. Mass spectrum: MH+=225.

To a slurry of 60% NaH (0.14 g, 3.5 mmol) in DMF (30 ml) at ice bathtemperature add, portionwise, the product of Step 1 (0.51 g, 3 mmol).When gas evolution ceases, add the product of Step 2. Stir the resultingmixture at RT overnight. Filter off dark red insoluble matter, andconcentrate the filtrate to dryness under vacuum. Triturate the gummyresidue with CH₃OH to give the title compound as a light yellow solid.Mass spectrum: MH+=358.

The product of Step 3 was treated as described in Preparation 1, Steps 2and 4, to obtain the compound of Example 1-2.

EXAMPLE 12

Step 1: To NaH (60% in oil, 142 mg, 3.5 mmol) in DMF (15 ml) add thechloride of Example 11, Step 1 (500 mg, 2.9 mmol). Add to this1-(2-chloroethyl)-4-(2,4-difluorophenyl)piperazine (846 mg, 3.5 mmol).Stir at RT 90 h and concentrate. Chromatograph to obtain the desiredcompound as a white solid. PMR in DMSO: δ2.57 (4H, s), 2.76 (2H, t),2.85 (4H, s), 4.30 (2H, t), 7.0 (2H, m), 7.15 (1H, dxt), 7.26 (2H, s),7.97(1 H, s).Step 2: Treat the chloride of Step 1 (37 mg, 0.095 mmol) in DMF (95 ml)with hydrazine hydrate (9.2 μl, 0.19 mmol). After 4 h, concentrate andchromatograph on PLC to obtain the hydrazine as a brown oil. Massspectrum: MH+=390.Step 3: Treat the hydrazine from Step 2 (18 mg, 0.047 mmol) in DMF (2ml) with thiophene-2-carbonyl chloride (5.2 μl, 0.047 mmol) and DIPEA(12.2 μl, 0.07 mmol). After 4 h, concentrate and chromatograph on PLC toobtain the hydrazide as a yellow oil. Mass spectrum: MH+=500.Step 4: Heat the hydrazide from Step 3 (13 mg, 0.026 mmol) inN,O-bis(trimethyl-silyl)acetamide (1 ml) for 2 h at 100° C. Concentrateand chromatograph on PLC to obtain the title compound as a white solid.Mass spectrum: MH+=482.

The 1-(2-chloroethyl)-4-(2,4-difluorophenyl)piperazine employed in thissequence is prepared in two steps. Add chloroacetyl chloride (1.76 ml,22.1 mmol) and N-methylmorpholine (2.65 ml, 24.1 mmol) to1-(2,4-difluorophenyl)piperazine (3.98 g, 20.1 mmol) in CH₂Cl₂ (15 ml)at 0° C. Stir at RT 1 h, concentrate, partition EtOAc-water, dry, andconcentrate to obtain the amide as a brown oil. To a 0° C. solution ofthis (4.71 g, 17.1 mmol) in THF (25 ml) add dropwise BH₃.CH₃S/THF (2M,12.8 ml, 25.6 mmol). Stir at RT overnight, quench with CH₃OH,concentrate, and partition with CH₂Cl₂-water. Dry and concentrate theorganic layer. Treat the crude product a second time with BH₃.CH₃S/THFand work up as above to provide the chloroethylpiperazine as a brownoil.

EXAMPLE 13

Step 1: To NaH (2.14 g, 60% in oil, 53 mmol) in DMF (20 ml), add theproduct of Example 11, Step 1 (7.55 g, 45 mmol). Add1-bromo-2-chloroethane (14.8 ml, 178 mmol). Stir 1.5 h and concentrate.Chromatograph to give the dichloride as a white solid.Step 2: To the product of Step 1 (3.7 g, 16 mmol) in DMF (20 ml) addt-butyl carbazate (2.53 g, 19 mmole). Heat at 80° C. for 18 h andconcentrate. Chromatograph to obtain the carbazate as a white solid.Step 3: To the product of Step 2 (3.16 g, 9.6 mmol) and KI (1.6 g, 9.6mmol) in DMF (25 ml) add 1-(2,4-difluorophenyl)piperazine (3.82 g, 19mmol). Heat at 90° C. for 68 h and concentrate. Chromatograph to obtainthe piperazine as a brown solid.Step 4: Dissolve the product of Step 3 (3.38 g, 6.9 mmol) in 1:1CH₃OH—CH₂Cl₂ (50 ml). Add 4M HCl in dioxane (20 ml). Stir 16 h and addaq. NH₃ to pH 11-12. Concentrate and chromatograph to obtain thehydrazine as a yellow solid.Step 5: Combine the product of Step 4 (0.120 g, 0.31 mmol) with5-bromo-2-furoic acid (0.071 g, 0.37 mmol) and HOBt.H₂O (0.050 g, 0.37mmol) in DMF (6 ml). Add EDCl (0.071 g, 0.37 mmol) and stir 1 h.Concentrate and chromatograph to obtain the hydrazide as a yellow solid.Step 6: Dissolve the product of Step 5 (0.163 g, 0.28 mmol) inN,O-bis(trimethylsilyl) acetamide (6 ml). Heat at 120° C. for 16 h andpour into CH₃OH. Concentrate and chromatograph to obtain the titleproduct as an off-white solid: MS m/e 544+546 (M+1).

Similarly prepare compounds of the following structure, wherein R is asdefined in the table:

Example R MS m/e 13-2

480 13-3

500, 502 13-4

465 13-5

479 13-6

544, 546 13-7

466 13-8

512 13-9

476 13-10

484

EXAMPLE 14

Treat the product of Example 13, Step 4 (0.080 g, 0.20 mmol) withnicotinoyl chloride hydrochloride (0.044 g, 0.25 mmol) anddiisopropylethylamine (0.086 ml, 0.49 mmol) in DMF (4 ml). Stir 2 h,concentrate and chromatograph to obtain the hydrazide as a white solid.

Treat this material with BSA as in Example 13, Step 6 to obtain thetitle compound as a white solid: MS m/e 477 (M+1).

Similarly prepare compounds of the following structure, wherein R is asdefined in the table:

Example R MS, m/e 14-2

511 14-3

494

EXAMPLE 15

Step 1: To the product of Example 13, Step 2 (3.54 g, 10.8 mmol) and KI(1.79 g, 10.8 mmol) in DMF (35 ml) add1-(4-(2-methoxyethoxy)phenyl)piperazine (5.1 g, 22 mmol). Heat at 90° C.for 90 h and concentrate. Chromatograph to obtain the piperazine as abrown solid.Step 2: Treat the product of Step 1 with HCl as in Example 13, Step 4,to obtain the hydrazine as a yellow solid.Step 3: Treat the product of Step 2 with 5-chloro-2-furoic acid as inExample 13, Step 5, to obtain the hydrazide as a yellow solid.Step 4: Treat the product of Step 3 with BSA as in Example 13, Step 6.Chromatograph to obtain the title compound as a white solid, MS m/e538+540 (M+1).

Similarly prepare compounds of the following structure, wherein R is asdefined in the table:

Example R MS, m/e 15-2

582, 584 15-3

532 15-4

550 15-5

522 15-6

518

EXAMPLE 16

Combine the product of Example 1-83 (0.080 g, 0.16 mmol) with Ac₂O(0.028 ml, 0.28 mmol) and 4-dimethylaminopyridine (0.004 g, 0.03 mmol)in DMF (5 ml). Stir 4 h, concentrate, and chromatograph to obtain theacetate ester as a white solid, MS: m/e=532 (M+1).

EXAMPLE 17

Combine the product of Example 1-21 (0.100 g, 0.21 mmol) with H₂NHOH.HCl0.029 g, 0.42 mmol) in 95% EtOH (9 ml). Add 10 drops conc. HCl, heat atreflux 5 h, add DMF (1.5 ml), heat 18 h, allow to cool, and filter toobtain the oxime as a white solid, MS: m/e=487 (M+1). Chromatograph themother liquor to obtain additional product.

Similarly prepare the methoxime, a white solid, MS: m/e=501 (M+1):

EXAMPLE 18

Step 1: To a solution of 4-bromophenethyl alcohol (0.600 g, 2.98 mmol)and 3-pyridinylboronic acid (0.734 g, 5.97 mmol) in toluene (35 ml) andEtOH (9 ml), add a solution of K₂CO₃ (0.8826 g, 5.97 mmol) in H₂O (16ml) and tetrakis(triphenyl-phosphine)palladium(0) (0.172 g, 0.149 mmol).Heat in a sealed tube 18 h at 120° C. and cool. Extract with EtOAc, washwith brine, dry (K₂CO₃) and concentrate. Chromatograph on silica (30-50%EtOAc/hexanes) to obtain the biaryl alcohol.Step 2: To the product of Step 1 (0.540 g, 2.71 mmol) in CH₂Cl₂ (15 ml)at 0° C. add mesyl chloride (0.35 ml, 3.52 mmol) and Et₃N (0.57 ml, 4.00mmol). Stir 2.5 h and extract with CH₂Cl₂. Dry (Na₂SO₄) and concentrateto obtain the mesylate.Step 3: Add the product of Preparation 4 (0.347 g, 1.44 mmol) to themesylate of Step 2 (0.480 g, 1.73 mmol) in DMF (4.5 ml), followed by NaH(60% in oil, 0.082 g, 4.04 mmol). Stir 18 h and extract with EtOAc. Washwith H₂O, dry (K₂CO₃) and concentrate. Purify by PTLC (5% CH₃OH/CH₂Cl₂,developed twice) to obtain the title compound as a white solid, MS: 423(M+1).

By the above method, prepare the following (Example 18-8 from commercialbiphenylethanol):

Example Z—Y— MS, m/e 18-2

468 18-3

452 18-4

466 18-5

506 18-6

453 18-7

423 18-8

422 18-9

423

EXAMPLE 19

Step 1: Combine 4-bromophenethyl alcohol (3.00 g, 14.9 mmol),triethylamine (2.68 ml, 19.2 mmol), dimethylaminopyridine (0.180 g, 1.47mmol) and t-butyldimethylsilyl chloride (2.45 g, 16.3 mmol) in CH₂Cl₂(75 ml). Stir 1 h, wash with H₂O, dry (K₂CO₃), and concentrate.Chromatograph on silica (hexanes) to obtain the silyl ether.

Step 2: To the compound of Step 1 (0.300 g, 0.95 mmol) in dry toluene(15 ml) add 2-(tri-butylstannyl)pyridine (1.05 g, 2.86 mmol) andtetrakis(triphenylphosphine)-palladium (0.11 g, 0.095 mmol). Flush withN₂ and heat 16 h at 120° C. Cool, filter through Celite, and wash withNH₄Cl, brine and then water. Dry (K₂CO₃) and concentrate. Chromatographon silica (3-5% EtOAc/hexanes) to obtain the biaryl, MS 314 (M+1).

Step 3: Combine the biaryl of Step 2 (0.180 g, 0.57 mmol) and TBAF (1.0M in THF, 1.7 ml) in THF (5.7 ml). Stir 2 h, wash with saturated NH₄Cl,and extract with EtOAc. Wash with H₂O several times, dry (K₂CO₃) andconcentrate to obtain the alcohol.

Steps 4 and 5: Conduct as in Example 18, Steps 2 and 3, to obtain thetitle compound as a white solid, MS: 423 (M+1).

Similarly prepare the following compounds:

EXAMPLE 20

To the product of Example 18 (0.055 g, 0.13 mmol) in CH₂Cl₂ (1.5 ml) at−78° C. add m-CPBA (0.050 g, 0.29 mmol). Allow to warm, stir 5 h, andwash successively with sat. Na₂S₂O₃, 5% K₂CO₃, and H₂O. Dry (Na₂SO₄) andconcentrate. Purify by PTLC (10% CH₃OH/CH₂Cl₂) to obtain the titlecompound, MS: 439 (M+1).

Similarly, oxidize the product of Example 18-2 at 0° C. or RT to producethe sulfoxide, MS: 484 (M+1), or the sulfone, MS: 500 (M+1).

EXAMPLE 21

Combine the product of Preparation 6 (0.104 g, 0.30 mmol),4-methyl-benzenethiol (0.075 g, 0.60 mmol), and K₂CO₃ (0.091 g, 0.66mmol) in DMF (20 ml). Heat at 80° C. for 5 h and concentrate. Partitionbetween EtOAc and water, wash with brine, dry over MgSO₄ andconcentrate. Recrystallize from CH₃OH to obtain the title compound, MS:m/e=392 (M+1).

Similarly prepare the following compounds:

Example Z MS, m/e 21-2

408 21-3

426, 428 21-4

394 21-5

379

EXAMPLE 22

Combine the product of Preparation 6 (0.11 g, 0.25 mmol),3,4-dimethoxy-phenol (0.154 g, 1.0 mmol), and K₂CO₃ (0.138 g, 1.0 mmol)in DMF (5 ml). Heat at 90° C. for 48 h and concentrate. Partitionbetween EtOAc and water, wash with 1 N NaOH and then brine, dry overMgSO₄, and concentrate. Chromatograph on silica (1.5% CH₃OH/CH₂Cl₂) toobtain the title compound, MS: m/e=422 (M+1).

Similarly prepare the following compound, MS: m/e=454 (M+1).

EXAMPLE 23

Step 1: To NaH (60% in oil, 1.32 g, 33 mmol) in DMF (25 ml) at 5° C. adddropwise, with stirring, 3,4-dimethoxyphenol (4.77 g, 30 mmol). After0.5 h, add 1,5-dibromo-pentane (20.7 g, 90 mmol). Stir 2 h andconcentrate. Chromatograph on silica (CH₂Cl₂) to obtain the monobromide,MS: m/e=303 (M+1).Step 2: To NaH (60% in oil, 0.044 g, 1.1 mmol) in DMF (25 ml) at 5° C.add the product of Preparation 1 (0.241 g, 1.1 mmol). After 0.5 h, addthe compound from Step 1. Allow to warm, stir 18 h, and concentrate.Partition between EtOAc and water, wash with 1 N NaOH and then brine,dry over MgSO₄, and concentrate. Chromatograph on silica (2%CH₃OH/CH₂Cl₂) and recrystallize the appropriate fraction from CH₃CN toobtain the title compound, MS: m/e=464 (M+1).

EXAMPLE 24

Step 1: Combine 1,4-dioxa-8-azaspiro(4,5)decane (0.48 ml, 3.8 mmol) withthe product of Preparation 2 (0.66 g, 1.5 mmol) in DMF (10 ml). Heat at90° C. for 16 h, allow to cool, filter and wash with CH₃OH to giveoff-white solid, MS: m/e 411 (M+1).Step 2: Heat the product of Step 1 (0.476 g, 1.16 mmol) in acetone (10ml) and 5% HCl (10 ml) at 100° C. for 16 h. Cool, neutralize with sat.NaHCO₃, and extract with 10% CH₃OH in CH₂Cl₂. Dry (MgSO₄), concentrateand chromatograph on silica with CH₃OH—CH₂Cl₂ to obtain the ketone as awhite powder, MS: m/e 367 (M+1).Step 3: Combine the product of Step 2 (0.050 g, 0.13 mmol) withO-methylhydroxyl-amine hydrochloride (0.033 g, 0.39 mmol) in pyridine (3ml). Stir for 16 h and concentrate. Partition between NaHCO₃ (sat.) and5% CH₃OH in CH₂Cl₂. Dry (MgSO₄), concentrate and chromatograph on silicawith 5% CH₃OH—CH₂Cl₂ to obtain the title compound as a white solid, MS:m/e 396 (M+1).

Similarly prepare the following compounds:

Example R¹¹ MS, m/e 24-2 —CH₂CH₃ 410 24-3 —CH₂CH₂CH₃ 424 24-4 —CH₂CHCH₂422 24-5 —C(CH₃)₃ 438 24-3 —C₆H₅ 458 24-4 —CH₂C₆H₅ 472

EXAMPLE 25

Step 1: Combine benzyl 4-oxo-1-piperidinecarboxylate (1.0 g, 4.3 mmol)with H₂NOH.HCl (0.89 g, 13 mmol) in pyridine (5 ml). Stir 16 h andconcentrate. Partition between NaHCO₃ (sat.) and EtOAc, dry (MgSO₄) andconcentrate to give the oxime.Step 2: Combine the product of Step 1 (0.44 g, 1.8 mmol) with2-bromoethyl methyl ether (0.20 ml, 2.2 mmol) and NaH (0.10 g, 2.7 mmol)in DMF (8 ml). Stir 16 h and concentrate. Partition between NH₄Cl (sat.)and ether, dry (MgSO₄), and concentrate. Chromatograph the residue onsilica with 20% EtOAc-hexane to obtain the alkylated oxime.Step 3: Stir the product of Step 2 (0.45 g, 1.47 mmol) over 5% Pd/C(0.045 g) in EtOAc (25 ml) under H₂ for 6 h. Filter and concentrate toobtain the amine.Step 4: Treat the amine of Step 3 with the product of Preparation 2 asin Example 24, Step 1, to obtain the title compound as a white solid,MS: m/e 440 (M+1).

EXAMPLE 26

Add sodium triacetoxyborohydride (0.083 g, 0.39 mmol) to a mixture ofthe product of Example 24, Step 2 (0.050 g, 0.13 mmol), aniline (0.035ml, 0.39 mmol), and AcOH (0.045 ml, 0.78 mmol) in dichloroethane (3 ml).Stir 16 h and partition between NaHCO₃ (sat.) and 5% CH₃OH in CH₂Cl₂.Dry (MgSO₄) and concentrate. Chromatograph (5% CH₃OH—CH₂Cl₂) to obtainthe title compound as a white solid, MS: m/e 444 (M+1).

In similar fashion, prepare the following compound, MS: m/e 445 (M+1).

EXAMPLE 27

Step 1: Combine 4-bromophenol (3.46 g, 20.0 mmol) with 2-bromoethylmethyl ether (2.82 ml, 30.0 mmol) and K₂CO₃ (8.30 g, 60.0 mmol) inacetone (50 ml). Heat at reflux 16 h, cool, filter, and concentrate.Chromatograph on silica with 5% EtOAc/hexane to give the ether as aclear oil. To this ether (2.73 g, 11.8 mmol) in dry THF (50 ml) at −78°C. add n-BuLi (1.6 M in hexane, 7.4 ml, 11.8 mmol). Stir for 10 min. andadd a solution of benzyl 4-oxo-1-piperidinecarboxylate (2.5 g, 10.7mmol) in dry THF (5 ml). Stir for 2 h and allow to warm. Partitionbetween sat. NH₄Cl and EtOAc, dry (MgSO₄) and concentrate. Chromatographon silica with EtOAc/hexane (20:80, then 40:60) to obtain the alcohol.Step 2: To a solution of the product of Step 1 (0.386 g, 1.0 mmol) andtriethylsilane (0.80 ml, 5.0 mmol) in dry CH₂Cl₂ (10 ml) at −78° C. addtrifluoroacetic acid (0.38 ml, 5.0 mmol). Allow to warm over 2 h andpartition between sat. NaHCO₃ and CH₂Cl₂. Dry (MgSO₄) and concentrate.Chromatograph on silica with 20% EtOAc/hexane to obtain the reductionproduct, MS: m/e 370 (M+1).Step 3: Stir the product of Step 2 (0.300 g, 0.758 mmol) over 5% Pd/C(0.030 g) in EtOAc (5 ml) and CH₃OH (5 ml) under H₂ for 2 h. Filter andconcentrate to obtain the amine.Step 4: Treat the amine of Step 3 with the product of Preparation 2 asin Example 24, Step 1, to obtain the title compound as a white solid,MS: m/e 503 (M+1).

EXAMPLE 28

Treat the product of Example 1-145 (0.020 g, 0.044 mmol) in EtOH (0.5ml) at 0° C. with sodium borohydride (0.005 g, 0.13 mmol) and with anequal amount again after 0.75 h. After another 0.75 h, partition betweenCH₂Cl₂ and sat. NH₄Cl. Dry (Na₂SO₄) and concentrate. Purify by PTLC (10%CH₃OH/CH₂Cl₂) to obtain the title compound as a white solid, MS: 459(M+1).

EXAMPLE 29

Treat the product of Example 1-145 (0.020 g, 0.044 mmol) in pyridine(0.5 ml) with methoxyamine hydrochloride (0.011 g, 0.13 mmol). Stir 16 hand concentrate. Partition between CH₂Cl₂ and sat. NaHCO₃. Dry (Na₂SO₄)and concentrate. Purify by PTLC (5% CH₃OH/CH₂Cl₂) to obtain the titlecompound as a white solid, MS: 486 (M+1).

Similarly, prepare the oxime 29-2 as two separated geometric isomers,each a white solid, MS: 472 (M+1).

Because of their adenosine A_(2a) receptor antagonist activity,compounds of the present invention are useful in the treatment ofdepression, cognitive function diseases and neurodegenerative diseasessuch as Parkinson's disease, senile dementia as in Alzheimer's disease,and psychoses of organic origin. In particular, the compounds of thepresent invention can improve motor-impairment due to neurodegenerativediseases such as Parkinson's disease.

The other agents known to be useful in the treatment of Parkinson'sdisease which can be administered in combination with the compounds offormula I include: L-DOPA; dopaminergic agonists such as quinpirole,ropinirole, pramipexole, pergolide and bromocriptine; MAO-B inhibitorssuch as deprenyl and selegiline; DOPA decarboxylase inhibitors such ascarbidopa and benserazide; and COMT inhibitors such as tolcapone andentacapone. One to three other agents can be used in combination withthe compounds of formula I, preferably one.

The pharmacological activity of the compounds of the invention wasdetermined by the following in vitro and in vivo assays to measureA_(2a) receptor activity.

Human Adenosine A_(2a) and A₁ Receptor Competition Binding AssayProtocol

Membrane sources:

A_(2a): Human A_(2a) Adenosine Receptor membranes, Catalog #RB-HA2a,Receptor Biology, Inc., Beltsville, Md. Dilute to 17 μg/100 μl inmembrane dilution buffer (see below).

Assay Buffers:

Membrane dilution buffer: Dulbecco's Phosphate Buffered Saline(Gibco/BRL)+10 mM MgCl₂.

Compound Dilution Buffer: Dulbecco's Phosphate Buffered Saline(Gibco/BRL)+10 mM MgCl₂ supplemented with 1.6 mg/ml methyl cellulose and16% DMSO. Prepared fresh daily.

Ligands:

A_(2a): [3H]—SCH 58261, custom synthesis, AmershamPharmacia Biotech,Piscataway, N.J. Stock is prepared at 1 nM in membrane dilution buffer.Final assay concentration is 0.5 nM.

A₁: [3H]— DPCPX, AmershamPharmacia Biotech, Piscataway, N.J. Stock isprepared at 2 nM in membrane dilution buffer. Final assay concentrationis 1 nM.

Non-specific Binding:

A_(2a): To determine non-specific binding, add 100 nM CGS 15923 (RBI,Natick, Mass.). Working stock is prepared at 400 nM in compound dilutionbuffer.

A₁: To determine non-specific binding, add 100 μM NECA (RBI, Natick,Mass.). Working stock is prepared at 400 μM in compound dilution buffer.

Compound Dilution:

Prepare 1 mM stock solutions of compounds in 100% DMSO. Dilute incompound dilution buffer. Test at 10 concentrations ranging from 3 μM to30 pM. Prepare working solutions at 4× final concentration in compounddilution buffer.

Assay procedure:

Perform assays in deep well 96 well plates. Total assay volume is 200μl. Add 50 μl compound dilution buffer (total ligand binding) or 50 μlCGS 15923 working solution (A_(2a) non-specific binding) or 50 μl NECAworking solution (A₁ non-specific binding) or 50 μl of drug workingsolution. Add 50 μl ligand stock ([3H]—SCH 58261 for A_(2a), [3H]— DPCPXfor A₁). Add 100 μl of diluted membranes containing the appropriatereceptor. Mix. Incubate at room temperature for 90 minutes. Harvestusing a Brandel cell harvester onto Packard GF/B filter plates. Add 45μl Microscint 20 (Packard), and count using the Packard TopCountMicroscintillation Counter. Determine IC₅₀ values by fitting thedisplacement curves using an iterative curve fitting program (Excel).Determine Ki values using the Cheng-Prusoff equation.

Haloperidol-induced Catalepsy in the Rat

Male Sprague-Dawley rats (Charles River, Calco, Italy) weighing 175-200g are used. The cataleptic state is induced by the subcutaneousadministration of the dopamine receptor antagonist haloperidol (1 mg/kg,sc), 90 min before testing the animals on the vertical grid test. Forthis test, the rats are placed on the wire mesh cover of a 25×43plexiglass cage placed at an angle of about 70 degrees with the benchtable. The rat is placed on the grid with all four legs abducted andextended (“frog posture”). The use of such an unnatural posture isessential for the specificity of this test for catalepsy. The time spanfrom placement of the paws until the first complete removal of one paw(decent latency) is measured maximally for 120 sec.

The selective A_(2A) adenosine antagonists under evaluation areadministered orally at doses ranging between 0.03 and 3 mg/kg, 1 and 4 hbefore scoring the animals.

In separate experiments, the anticataleptic effects of the referencecompound, L-DOPA (25, 50 and 100 mg/kg, ip), were determined.

6-OHDA Lesion of the Middle Forebrain Bundle in Rats

Adult male Sprague-Dowley rats (Charles River, Calco, Como, Italy),weighing 275-300 g, are used in all experiments. The rats are housed ingroups of 4 per cage, with free access to food and water, undercontrolled temperature and 12 hour light/dark cycle. The day before thesurgery the rats are fasted over night with water ad libitum.

Unilateral 6-hydroxydopamine (6-OHDA) lesion of the middle forebrainbundle is performed according to the method described by Ungerstedt etal. (Brain Research, 1971, 6-OHDA and Cathecolamine Neurons, NorthHolland, Amsterdam, 101-127), with minor changes. Briefly, the animalsare anaesthetized with chloral hydrate (400 mg/kg, ip) and treated withdesipramine (10 mpk, ip) 30 min prior to 6-OHDA injection in order toblock the uptake of the toxin by the noradrenergic terminals. Then, theanimals are placed in a stereotaxic frame. The skin over the skull isreflected and the stereotaxic coordinates (−2.2 posterior from bregma(AP), +1.5 lateral from bregma (ML), 7.8 ventral from dura (DV) aretaken, according to the atlas of Pellegrino et al (Pellegrino L. J.,Pellegrino A. S. and Cushman A. J., A Stereotaxic Atlas of the RatBrain, 1979, New York: Plenum Press). A burr hole is then placed in theskull over the lesion site and a needle, attached to a Hamilton syringe,is lowered into the left MFB. Then 8 μg 6-OHDA—HCl is dissolved in 4 μlof saline with 0.05% ascorbic acid as antioxidant, and infused at theconstant flow rate of 1 μl/1 min using an infusion pump. The needle iswithdrawn after additional 5 min and the surgical wound is closed andthe animals left to recover for 2 weeks.

Two weeks after the lesion the rats are administered with L-DOPA (50mg/kg, ip) plus Benserazide (25 mg/kg, ip) and selected on the basis ofthe number of full contralateral turns quantified in the 2 h testingperiod by automated rotameters (priming test). Any rat not showing atleast 200 complete turns/2h is not included in the study.

Selected rats receive the test drug 3 days after the priming test(maximal dopamine receptor supersensitivity). The new A_(2A) receptorantagonists are administered orally at dose levels ranging between 0.1and 3 mg/kg at different time points (i.e., 1, 6, 12 h) before theinjection of a subthreshold dose of L-DOPA (4 mpk, ip) plus benserazide(4 mpk, ip) and the evaluation of turning behavior.

Using the above test procedures, the following results were obtained forpreferred and/or representative compounds of the invention.

Results of the binding assay on compounds of the invention showed A_(2a)Ki vaules of 0.3 to 57 nM, with preferred compounds showing Ki valuesbetween 0.3 and 5.0 nM.

Selectivity is determined by dividing Ki for A1 receptor by Ki forA_(2a) receptor. Preferred compounds of the invention have a selectivityranging from about 100 to about 2000.

Preferred compounds showed a 50-75% decrease in descent latency whentested orally at 1 mg/kg for anti-cataleptic activity in rats.

In the 6-OHDA lesion test, rats dosed orally with 1 mg/kg of thepreferred compounds performed 170-440 turns in the two-hour assayperiod.

In the haloperidol-induced catalepsy test, a combination ofsub-threshold amount of a compound of formula I and a sub-thresholdamount of L-DOPA showed a significant inhibition of the catalepsy,indicating a synergistic effect. In the 6-OHDA lesion test, test animalsadministered a combination of a compound of formula I and asub-threshold amount of L-DOPA demonstrated significantly highercontralateral turning.

For preparing pharmaceutical compositions from the compounds describedby this invention, inert, pharmaceutically acceptable carriers can beeither solid or liquid. Solid form preparations include powders,tablets, dispersible granules, capsules, cachets and suppositories. Thepowders and tablets may be comprised of from about 5 to about 70 percentactive ingredient. Suitable solid carriers are known in the art, e.g.magnesium carbonate, magnesium stearate, talc, sugar, lactose. Tablets,powders, cachets and capsules can be used as solid dosage forms suitablefor oral administration.

For preparing suppositories, a low melting wax such as a mixture offatty acid glycerides or cocoa butter is first melted, and the activeingredient is dispersed homogeneously therein as by stirring. The moltenhomogeneous mixture is then poured into convenient sized molds, allowedto cool and thereby solidify.

Liquid form preparations include solutions, suspensions and emulsions.As an example may be mentioned water or water-propylene glycol solutionsfor parenteral injection.

Liquid form preparations may also include solutions for intranasaladministration.

Aerosol preparations suitable for inhalation may include solutions andsolids in powder form, which may be in combination with apharmaceutically acceptable carrier, such as an inert compressed gas.

Also included are solid form preparations which are intended to beconverted, shortly before use, to liquid form preparations for eitheroral or parenteral administration. Such liquid forms include solutions,suspensions and emulsions.

The compounds of the invention may also be deliverable transdermally.The transdermal compositions can take the form of creams, lotions,aerosols and/or emulsions and can be included in a transdermal patch ofthe matrix or reservoir type as are conventional in the art for thispurpose.

Preferably the compound is administered orally.

Preferably, the pharmaceutical preparation is in unit dosage form. Insuch form, the preparation is subdivided into unit doses containingappropriate quantities of the active component, e.g., an effectiveamount to achieve the desired purpose.

The quantity of active compound of formula I in a unit dose ofpreparation may be varied or adjusted from about 0.1 mg to 1000 mg, morepreferably from about 1 mg to 300 mg, according to the particularapplication.

The actual dosage employed may be varied depending upon the requirementsof the patient and the severity of the condition being treated.Determination of the proper dosage for a particular situation is withinthe skill of the art. Generally, treatment is initiated with smallerdosages which are less than the optimum dose of the compound.Thereafter, the dosage is increased by small increments until theoptimum effect under the circumstances is reached. For convenience, thetotal daily dosage may be divided and administered in portions duringthe day if desired.

The amount and frequency of administration of the compounds of theinvention and the pharmaceutically acceptable salts thereof will beregulated according to the judgment of the attending clinicianconsidering such factors as age, condition and size of the patient aswell as severity of the symptoms being treated. A typical recommendeddosage regimen for compounds of formula I is oral administration of from10 mg to 2000 mg/day preferably 10 to 1000 mg/day, in two to fourdivided doses to provide relief from central nervous system diseasessuch as Parkinson's disease. The compounds are non-toxic whenadministered within this dosage range.

The doses and dosage regimen of the dopaminergic agents will bedetermined by the attending clinician in view of the approved doses anddosage regimen in the package insert, taking into consideration the age,sex and condition of the patient and the severity of the disease. It isexpected that when the combination of a compound of formula I and adopaminergic agent is administered, lower doses of the components willbe effective compared to the doses of the components administered asmonotherapy.

The following are examples of pharmaceutical dosage forms which containa compound of the invention. Those skilled in the art will recognizethat dosage forms can be modified to contain both a compound of formulaI and a dopaminergic agent. The scope of the invention in itspharmaceutical composition aspect is not to be limited by the examplesprovided. EXAMPLE A Pharmaceutical Dosage Form Examples Tablets No.Ingredients mg/tablet mg/tablet 1. Active compound 100 500 2. LactoseUSP 122 113 3. Corn Starch, Food Grade, as a 30 40 10% paste in PurifiedWater 4. Corn Starch, Food Grade 45 40 5. Magnesium Stearate 3 7 Total300 700

Method of Manufacture

Mix Item Nos. 1 and 2 in a suitable mixer for 10-15 minutes. Granulatethe mixture with Item No. 3. Mill the damp granules through a coarsescreen (e.g., ¼″, 0.63 cm) if necessary. Dry the damp granules. Screenthe dried granules if necessary and mix with Item No. 4 and mix for10-15 minutes. Add Item No. 5 and mix for 1-3 minutes. Compress themixture to appropriate size and weigh on a suitable tablet machine.EXAMPLE B Capsules No. Ingredient mg/capsule mg/capsule 1. Activecompound 100 500 2. Lactose USP 106 123 3. Corn Starch, Food Grade 40 704. Magnesium Stearate NF 7 7 Total 253 700

Method of Manufacture

Mix Item Nos. 1, 2 and 3 in a suitable blender for 10-15 minutes. AddItem No. 4 and mix for 1-3 minutes. Fill the mixture into suitabletwo-piece hard gelatin capsules on a suitable encapsulating machine.

While the present invention has been described in conjunction with thespecific embodiments set forth above, many alternatives, modificationsand variations thereof will be apparent to those of ordinary skill inthe art. All such alternatives, modifications and variations areintended to fall within the spirit and scope of the present invention.

1. to
 14. (Canceled)
 15. A process of preparing a compound of formula II

wherein R is R¹-furanyl, R¹-thienyl, R¹-pyridyl, R¹-pyridyl N-oxide,R¹-oxazolyl, R¹⁰-phenyl, R¹-pyrrolyl or C₄-C₆ cycloalkenyl; R¹ is 1 to 3substituents independently selected from hydrogen, C₁-C₆-alkyl, —CF₃,halogen, —NO₂, —NR¹²R¹³, C₁-C₆ alkoxy, C₁-C₆ alkylthio, C₁-C₆alkylsulfinyl, and C₁-C₆ alkylsulfonyl; R¹⁰ is 1 to 5 substituentsindependently selected from the group consisting of hydrogen, halogen,C₁-C₆ alkyl, hydroxy, C₁-C₆ alkoxy, —CN, —NH₂, C₁-C₆alkylamino,di-((C₁-C₆)alkyl)amino, —CF₃, —OCF₃ and —S(O)₀₋₂(C₁-C₆)alkyl; R¹² is Hor C₁-C₆ alkyl; and R¹³ is (C₁-C₆)alkyl-C(O)— or (C₁-C₆)alkyl-SO₂—;comprising (1) treating 2-amino-4,6-dihydroxypyrimidine

with POCl₃ in dimethylformamide to obtain2-amino-4,6-dichloropyrimidine-5-carboxaldehyde

(2) treating carboxaldehyde VII with a hydrazide of the formulaH₂N—NH—C(O)—R, wherein R is as defined above, to obtain

(3) treating the intermediate of formula VIII with hydrazine hydrate toform a pyrazolo ring, thus obtaining the intermediate of formula IX

(4) forming the desired compound of formula II by dehydrativerearrangement.
 16. A process for preparing a compound of the formula II

wherein R is R¹-furanyl, R¹-thienyl, R¹-pyridyl, R¹-pyridyl N-oxide,R¹-oxazolyl, R¹⁰-phenyl, R¹-pyrrolyl or C₄-C₆ cycloalkenyl; R¹ is 1 to 3substituents independently selected from hydrogen, C₁-C₆-alkyl, —CF₃,halogen, —NO₂, —NR¹²R¹³, C₁-C₆ alkoxy, C₁-C₆ alkylthio, C₁-C₆alkylsulfinyl, and C₁-C₆ alkylsulfonyl; R¹⁰ is 1 to 5 substituentsindependently selected from the group consisting of hydrogen, halogen,C₁-C₆ alkyl, hydroxy, C₁-C₆ alkoxy, —CN, —NH₂, C₁-C₆alkylamino,di-((C₁-C₆)alkyl)amino, —CF₃, —OCF₃ and —S(O)₀₋₂(C₁-C₆)alkyl; R¹² is Hor C₁-C₆ alkyl; and R¹³ is (C₁-C₆)alkyl-C(O)— or (C₁-C₆)alkyl-SO₂—;comprising converting a compound of formula IX

into the desired compound of formula II by dehydrative rearrangement.17. A process for preparing a compound of formula IIIa

wherein R is R¹-furanyl, R¹-thienyl, R¹-pyridyl, R¹-pyridyl N-oxide,R¹-oxazolyl, R¹⁰-phenyl, R¹-pyrrolyl or C₄-C₆ cycloalkenyl; R¹ is 1 to 3substituents independently selected from hydrogen, C₁-C₆-alkyl, —CF₃,halogen, —NO₂, —NR¹²R¹³, C₁-C₆ alkoxy, C₁-C₆ alkylthio, C₁-C₆alkylsulfinyl, and C₁-C₆ alkylsulfonyl; R¹⁰ is 1 to 5 substituentsindependently selected from the group consisting of hydrogen, halogen,C₁-C₆ alkyl, hydroxy, C₁-C₆ alkoxy, —CN, —NH₂, C₁-C₆alkylamino,di-((C₁-C₆)alkyl)amino, —CF₃, —OCF₃ and —S(O)₀₋₂(C₁-C₆)alkyl; R¹² is Hor C₁-C₆ alkyl; and R¹³ is (C₁-C₆)alkyl-C(O)— or (C₁-C₆)alkyl-SO₂—;comprising (1) treating a chloride of formula VIII

with a hydroxyalkyl hydrazine of the formula HO—(CH₂)_(r)—NHNH₂, whereinr is 2-6, to obtain

(2) cyclizing the intermediate of formula X by dehydrative rearrangementto obtain the tricyclic intermediate of formula XI

and (3) converting the hydroxy compound of formula XI to the bromide offormula IIIa.
 18. to
 20. (Canceled)